The described subject matter relates generally to aircraft landing gear, and more specifically to steering systems for aircraft landing gear.
Main landing gear for large aircraft have traditionally employed a telescoping shock-absorbing strut with a multi-wheel truck attached. Such structures can effectively handle and react various forces seen during ground maneuvers. In order to assist in turning the aircraft, reduce side loads acting upon landing gear during turns, and reduce tire scrubbing, main landing gears with six or more wheeled bogie beam configurations have utilized a steerable forward or aft axle. Most common approaches to provide for forward or aft axle steering have utilized hydraulic actuators connected to directly or indirectly push or pull the aft axle to the desired steering angle.
Traditional push-pull steering systems are sized to produce enough steering torque at the minimum moment arm. As a result, the available steering torque is higher than required for most of the steerable range. Further, these systems have traditionally been configured such that the midrange of the actuator stroke corresponds to a neutral or 0° steering position. This provides equal range of motion of the steerable axle(s) and equal maximum steering angles in both the clockwise and counterclockwise directions. However, this range is not always needed in aircraft with main landing gears installed laterally apart from the aircraft center line. As such, one or more of the steerable landing gear axles rarely, if ever, will need their full range of angular motion to avoid tire scrubbing.